Support DELETE FROM T1 USING T2 WHERE ...

[francois-secherre]

Support for DELETE FROM USING queries, from postgres

https://www.postgresql.org/docs/11/sql-delete.html

Example:

DELETE FROM films USING producers
WHERE producer_id = producers.id AND producers.name = 'foo';

[coveralls]

Coverage increased (+0.03%) to 88.868% when pulling 9b81814 on fanchuo:feature/delete_using into aec76ea on JSQLParser:master.

[wumpz]

Thx for improving JSqlParser.